Differences in the hypothalamic-pituitary-adrenal axis of black and white women

Alterations in the activity of the hypothalamic-pituitary-adrenal (HPA) axis have been associated with obesity in humans and animals. To explore possible mechanisms responsible for the higher prevalence of obesity and its associated comorbid conditions in the black population, we studied the HPA axis of 18 black and 30 white weight- and age-matched nonobese and obese women. Waist to hip ratio, 24-h urinary free cortisol excretion, plasma cortisol responses to dexamethasone, and plasma ACTH and cortisol responses to 1 micrograms/kg ovine CRH were determined. There were no racial differences in waist to hip ratio, 24-h urinary free cortisol excretion, dexamethasone suppressibility of plasma cortisol, baseline plasma cortisol and ACTH concentrations, or plasma cortisol response to CRH. However, CRH-stimulated plasma ACTH concentrations, measured in an extraction polyclonal RIA, were significantly greater in blacks than in whites at all time points, beginning 5 min after the administration of CRH [area under the curve (AUC), 2463 +/- 288 pmol/L.min in blacks vs. 1185 +/- 78 in whites; P < 0.001]. These differences persisted when ACTH was measured by a 2-site direct immunoradiometric assay measuring the intact ACTH-(1-39) molecule (AUC, 1292 +/- 177 pmol/L.min in blacks vs. 504 +/- 95 in whites; P < 0.002). There was no significant correlation between body mass index and either cortisol or ACTH AUCs for either race, with blacks showing persistently elevated AUC for ACTH compared to whites, regardless of weight. We conclude that there are differences in the HPA axis of black and white women. How these differences may relate to the increased prevalence of obesity in the black population remains to be determined.

Normal dexamethasone suppression in obese binge and nonbinge eaters with rapid weight loss

Natural or experimental starvation is frequently associated with hypercortisolism, reflected as incomplete suppression of serum cortisol after dexamethasone. To determine whether rapid weight loss per se or some other aspect of starvation induces disruption of the hypothalamic-pituitary-adrenal (HPA) axis, we evaluated 2 categories of obese women (body mass index > 30 kg/m2) undergoing rapid weight loss: binge eaters (n = 12) and nonbinge eaters (n = 8). We performed psychometric evaluation and 1 mg overnight dexamethasone suppression tests in the obese subjects, as well as in 12 race- and age-matched normal-weight women. The obese women were tested before and after 12 weeks of a 3349 kJ/day (800 kcal/day) liquid formula diet, and lost an average of 19.3 kg, which represented 17.3% of their total body weight. Binge eaters, who were initially more depressed than either nonbinge eaters or normal-weight controls, had a significant amelioration of their symptoms with weight loss. Neither group had evidence of disruption of the HPA axis before or after weight loss. Thus, the rate of failure to suppress cortisol after dexamethasone was approximately 10% in each of the obese and control groups, and did not differ between the pre- and postweight loss condition or between binge eaters and nonbinge eaters. Serum free T4 was unchanged, whereas T3 fell significantly with weight loss. We conclude that weight loss may improve affect in the obese without altering HPA axis activity, and postulate that one of the concomitants of restricted energy intake, perhaps in combination with a threshold body weight, may be of greater importance in causing abnormalities of dexamethasone suppression testing than rapid weight loss per se.

A practical approach to treatment of the obese patient

Obesity is one of the most common conditions encountered by primary care physicians, yet both physicians and patients are often frustrated by current approaches to its management. Recent advances in our understanding of obesity enable the physician to evaluate the contributions of biologic and environmental factors to the patient's obesity, to determine the degree of medical risk posed by the obesity, and to establish realistic goals for treatment. The chronic and relapsing nature of obesity requires ongoing support and vigilance. An individualized approach to obesity management, based on careful evaluation of biologic, psychologic, and social factors, can be successfully developed and implemented by the office-based primary care physician.

Food selection and intake of obese women with binge-eating disorder

We studied food selection and intake of 19 women [body mass index (in kg/m2) > 30] [corrected], 10 of whom met proposed DSM-IV criteria for binge-eating disorder (BED). All subjects ate two multicourse meals in the laboratory, and were given tape-recorded instructions at each meal either to binge or eat in a normal fashion. Subjects with BED consumed significantly more energy than did subjects without BED at both the binge [12,400 vs 8440 kJ (2963 vs 2017 kcal), P < 0.005] and normal [9810 vs 6870 kJ (2343 vs 1640 kcal), P < 0.02] meals. During the binge meal subjects with BED consumed a greater percentage of energy as fat (38.9% vs 33.5%, P < 0.002) and a lesser percentage as protein (11.4% vs 15.4%, P < 0.01) than did subjects without BED. There were no differences in macronutrient composition of food choices between groups in the normal meal. Obese women who meet criteria for BED show differences in both intake and macronutrient composition of food choices from obese women who do not meet these criteria when asked to eat in a laboratory setting, supporting the validity of this new diagnosis.

Telephone triage by primary care physicians

To determine if experienced primary care physicians are more likely to reach correct decisions on the telephone than their less experienced colleagues, we asked 31 first-year and 29 third-year residents, 21 faculty, and 36 private practitioners in pediatrics and family practice to evaluate three pediatric patients via a telephone interview with a simulated mother and to decide whether each patient needed to be seen that evening. Compared with first-year residents, the third-year residents, faculty and private practitioners decided less frequently to see children who were not severely ill (P less than .05) or injured (P less than .01); however, less than half obtained histories considered adequate to rule out potential serious illnesses. Faculty did better than either residents or private practitioners in managing a severely dehydrated child; 100% of the faculty, but less than 60% of the residents or private practitioners, chose to see the patient promptly (P less than .001). More than one third of all residents and private practitioners reached inappropriate management decisions despite obtaining information that should have altered their decisions. In these simulations, experience in private practice was not associated with improved telephone management of very sick children. Faculty physicians appeared to be better able to identify severely ill children without inappropriately evaluating those who were less ill. In all three simulations, attainment of the correct decision appeared to be determined not by the number or type of questions asked, but rather by the physician's interpretation of the information collected.

Bulimia nervosa: the role of the family physician

Bulimia nervosa is an eating disorder characterized by binge eating and purging. The disorder is estimated to occur in up to 5 percent of young women. Despite severe psychosocial impairment and potentially serious medical complications, patients do not usually reveal their bulimic behavior to a physician unless directly asked. Promising treatments include cognitive-behavioral psychotherapy and antidepressant medications.